package concurrency;

import java.util.Random;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * @author: zhangzeli
 * @date 8:43 2018/4/10
 * <P></P>
 */
public class ReadWriteLockDemo {
    private static Lock lock = new ReentrantLock();
    private static ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
    private static Lock readLock =readWriteLock.readLock();
    private static Lock writeLock = readWriteLock.writeLock();
    private int value;

    public Object handleRead(Lock lock) throws InterruptedException{
        try {
            lock.lock();
            Thread.sleep(1000);
            return value;
        }finally {
            lock.unlock();
        }
    }

    public void handleWrite(Lock lock,int index) throws InterruptedException{
        try {
            lock.lock();
            Thread.sleep(1000);
            value =index;
        }finally {
            lock.unlock();
        }
    }

    public static void main(String[] args) {
        final ReadWriteLockDemo demo = new ReadWriteLockDemo();
        Runnable readRunnale = new Runnable() {
            @Override
            public void run() {
                try {
                    demo.handleRead(lock);
                    //demo.handleRead(readLock);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        };

        Runnable write = new Runnable() {
            @Override
            public void run() {
                try {
                    //demo.handleWrite(writeLock,new Random().nextInt());
                    demo.handleWrite(lock,new Random().nextInt());
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        };

        for(int i=0;i<18;i++){
            new Thread(readRunnale).start();
        }
        for(int i=18;i<20;i++){
            new Thread(write).start();
        }
    }
}
